JPH07297442A - Radiation detector and ct device using it - Google Patents

Abstract

PURPOSE:To easily take out a signal line without interfering adjacent channels by positioning substrates for wiring along the lower surface of a radiation detector to which optical sensors are fitted and connecting the substrates to the optical sensors. CONSTITUTION:A scintillator 11 which converts radiation made incident to a radiation detecting surface into optical signals is formed. Photodiodes 13 which convert optical signals into electric signals are constituted on the lower surface of the scintillator 11 in a state where the photodiodes 13 are inclined against the scintillator 11 and light guides 12 which are made of glass, etc., and transmit the optical signals without allowing the signals to leak out are arranged between the scintillator 11 and photodiodes 13. Then substrates 14 are fitted in parallel to the photodiodes 13 and connected to the photodiodes 13 through signal lines 15. Therefore, the signals detected by the photodiodes 13 are transmitted to the substrates 14 through the signal lines 15 and the wiring connecting the photodiode 13 of each channel of a radiation detector to the substrates 14 do not interfere other channels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation detector constructed by arranging radiation detector channels in a two-dimensional array.

[0002]

2. Description of the Related Art In recent years, X-ray CT apparatuses have been widely used as medical diagnostic apparatuses have been developed. In an X-ray CT apparatus, an X-ray tube and an X-ray detector are arranged to face each other with a subject interposed therebetween, and X-rays emitted from the X-ray tube and transmitted through the subject are collected by the X-ray detector to obtain a tomographic image. The image is reconstructed. FIG. 4 is an explanatory view schematically showing the principle of such an X-ray CT apparatus.

In FIG. 1, when a high voltage is applied to the X-ray tube 1 and X-rays are emitted, the X-ray beam 7 is irradiated via the wedge 2 onto the subject 3 placed on the bed 4. The transmitted X-rays are collected by the X-ray detector 5, converted into electric signals, and output to the image reconstructing apparatus side via the data collecting apparatus 6.

The X-ray detector 5 usually has a one-dimensional arrangement, but in recent years, due to an attempt to capture a plurality of tomographic images with one scan, the detector chip has a two-dimensional array. The X-ray detectors arranged in the shape of a circle are being put to practical use. As a method of constructing such a two-dimensional X-ray detector, a method of combining a scintillator and an optical sensor can be considered.

When a photodiode is used as an optical sensor, if the pitch per detector channel is reduced, the proportion of the wiring area for extracting the electric signal from the sensitive layer increases, and an active area of the required size is obtained. I will not be able to.

Further, it is necessary to take out the signal line (wire bonding) from the photodiode of each channel, but it is difficult and unrealizable to take out the signal line from each channel arranged in a two-dimensional array. There are drawbacks.

[0007]

As described above, the conventional two-dimensional radiation detector requires a wiring area for each channel. Therefore, if the pitch between the channels is reduced, an active area of the required size is obtained. It cannot be downsized to a desired size. Also,
There is a drawback that it is difficult to take out the signal line from each channel arranged in a two-dimensional array.

The present invention has been made in order to solve such a conventional problem, and an object thereof is to easily take out a signal line from each channel, and
It is an object of the present invention to provide a radiation detector capable of obtaining a sufficient active area even if the pitch between channels is made small, and a CT apparatus using the radiation detector.

[0009]

In order to achieve the above object, the radiation detector of the first invention of the present application is a two-dimensional array of radiation detector channels having a scintillator on the upper surface and an optical sensor on the lower surface. In the radiation detector configured to convert incident radiation into an electric signal, the lower surface of the radiation detector is inclined with respect to the upper surface, and a plurality of substrates are arranged in parallel with the inclined lower surface. The feature is that a signal line for transmitting a detection signal is provided between the sensor and the sensor.

The radiation detector according to the second invention of the present application is
A radiation detector that is configured by two-dimensionally arranging radiation detector channels having a scintillator on the upper surface and a photosensor on the lower surface, and converts the incident radiation into an electric signal. The lower surface is inclined with respect to the upper surface. In this configuration, a substrate that is in contact with the lower surface and is substantially parallel to the upper surface is provided, and a signal line for transmitting a detection signal is provided between the substrate and the optical sensor.

Further, the radiation detector of the third invention of the present application is constructed by arranging radiation detector channels two-dimensionally,
In a radiation detector for converting incident radiation into an electric signal, the radiation detector channel includes a scintillator provided on a radiation incident surface, a mirror for reflecting an optical signal from the scintillator in a substantially perpendicular direction, and the scintillator. And an optical sensor that is arranged substantially at a right angle to the incident surface of the optical sensor for converting an optical signal from the mirror into an electric signal, and a plurality of substrates parallel to the surface of the optical sensor are provided. A signal line for transmitting a detection signal is provided between the two.

The radiation detector of the fourth invention of the present application is
In the first to third inventions, a reflective material for preventing crosstalk between channels is provided in a region between the scintillator and the optical sensor.

Further, the radiation detector of the fifth invention of the present application is
In the first to fourth inventions, the photosensor is a photodiode.

Further, the CT apparatus of the sixth invention of the present application is characterized in that a tomographic image of a subject is taken by using the radiation detector of the first invention to the fifth invention.

[0015]

In the radiation detector of the first invention of the present application constructed as described above, the lower surface side on which the optical sensor is mounted is inclined, and the wiring substrate is arranged along this inclination to form the optical sensor. The connection is made. Therefore, the signal line can be easily taken out without interfering with the adjacent channel.

In the second invention of the present application, the lower surface side of the detector is also inclined, and the signal line is connected between the optical sensor and the substrate mounted on the lower side of the detector and parallel to the upper surface. Done. At this time, since the lower surface of the detector is inclined, a sufficient space can be secured between the detector and the substrate, and the signal line can be easily taken out.

In the third invention of the present application, the optical signal converted by the scintillator is reflected by the mirror in the direction at right angles, and is received by the optical sensor mounted at right angles to the scintillator. Since the substrate to which the optical sensor and the signal line are connected is arranged in parallel with the optical sensor, the signal line can be easily taken out without interfering with the adjacent channel.

In the CT apparatus of the sixth invention of the present application, 2
Since the dimensional radiation detector is configured as shown in the first to fifth inventions, it is possible to obtain a plurality of tomographic images by one scan.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a first embodiment of a radiation detector according to the present invention. As shown in the figure, this radiation detector is constructed by arranging detector channels 16 in a two-dimensional array, and a scintillator 11 for converting incident radiation into an optical signal is formed on the radiation detecting surface (upper surface). Has been done. Further, the lower surface is inclined with respect to the upper surface, and the photodiode 1 for converting an optical signal into an electric signal is provided.
3 is formed. Further, between the scintillator 11 and the photodiode 13, an optical guide 12 formed of a material such as glass and transmitting an optical signal without leaking to the outside is disposed.

Further, a substrate 14 is attached in parallel with the photodiode 13, and the photodiode 13 and the substrate 14 are attached.
Are connected to each other via a signal line 15. As a result, the signal detected by the photodiode 13 is transmitted to the substrate 14 via the signal line 15.

According to the present embodiment thus constructed,
Photodiode 13 and substrate 1 for each channel of the detector
The wiring connecting with 4 does not interfere with other channels, and the connection of the signal line becomes easy. Also, the signal line 1
Since the wiring space of 5 is secured on the lower surface side of the detector,
It is possible to secure a sufficient active area even if the pitch per channel is reduced without requiring a wiring space on the upper surface side.

In the present embodiment, when the directivity of light is poor and there is crosstalk due to scattering, the side surface of the light guide may be surrounded by a reflector or coated with a reflective material. A light guide such as an optical fiber may be used as the light guide. Further, the detection signal transmitted to the substrate 14 may be extracted by connecting a flexible cable or by a connector on the surface opposite to the surface connected to the photodiode 13.

FIG. 2 shows a second radiation detector according to the present invention.
It is a block diagram which shows an Example. In the figure, the scintillator 11, the photodiode 13 and the light guide 12 which are arranged to be inclined with respect to the scintillator 11 have the same configuration as that of the first embodiment, and in this embodiment, the photodiode 13 is provided. A substrate 17 connected to the scintillator 11 is disposed parallel to the scintillator 11 (upper surface of the detector).

Even in such a structure, it is possible to secure a space for arranging the signal line 15 on the lower surface side of the detector. Therefore, as in the first embodiment, the photo of each channel of the detector is obtained. The wiring connecting the diode 13 and the substrate does not interfere with other channels, and the signal line can be easily connected. Also, the pitch per channel can be reduced. In the first and second embodiments, the light guide 12 made of a material such as glass is provided between the scintillator 11 and the photodiode 13, but the entire light guide 12 is formed by the scintillator 11. You may comprise.

FIG. 3 shows a third radiation detector according to the present invention.
It is a block diagram which shows an Example. As shown in the figure, this detector includes a scintillator 11 arranged on a radiation incident surface,
A mirror 19 for reflecting an optical signal converted by the scintillator 11 in a right-angle direction, and a photodiode arranged orthogonal to the scintillator 11 for receiving the optical signal from the mirror 19 and converting it into an electric signal. 13 and 13.

A substrate 18 is arranged in parallel with the photodiode 13 and is connected by a signal line 15 so that a detection signal from the photodiode 13 can be transmitted.

With this structure, a sufficient space for arranging the signal line 15 can be secured. Therefore, as in the first and second embodiments, the photodiode 13 of each channel of the detector is provided. The wiring connecting to the substrate does not interfere with other channels, and the signal line can be easily connected. Also, the pitch per channel can be reduced. In the third embodiment as well, the scintillator 11 may constitute the light guide 12 without using the light guide 12.

Further, in this embodiment, when the directivity of light is poor and there is crosstalk due to scattering, the side surface of the light guide may be surrounded by a reflector or coated with a reflective material.

[0029]

As described above, according to the present invention,
Since the wiring for connecting the photodiode and the substrate provided in each channel of the radiation detector can be arranged without interfering with other channels, the signal line can be easily connected. In addition, since no wiring space is required on the radiation incident surface side, the space per channel can be reduced, and a sufficient active area can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a radiation detector according to a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a radiation detector according to a second exemplary embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a radiation detector according to a third exemplary embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a schematic configuration of an X-ray CT apparatus.

[Explanation of symbols]

1 X-ray tube 3 Subject 5 X-ray detector 11
Scintillator 12 light guide 13 photodiode 14,
17, 18 Substrate 15 Signal line 16 Detector channel 19 Mirror

Claims (6)

[Claims] 1. A radiation detector configured to two-dimensionally arrange radiation detector channels having a scintillator on an upper surface and an optical sensor on a lower surface, and converting incident radiation into an electric signal. Radiation detection characterized in that the lower surface is inclined with respect to it, a plurality of substrates are arranged in parallel to the inclined lower surface, and a signal line for transmitting a detection signal is provided between the substrate and the optical sensor. vessel. 2. A radiation detector configured to two-dimensionally arrange radiation detector channels having a scintillator on the upper surface and a photosensor on the lower surface, and converting incident radiation into an electrical signal. In contrast, the lower surface is inclined, a substrate that is in contact with the lower surface and is substantially parallel to the upper surface is provided, and a signal line for transmitting a detection signal is provided between the substrate and the optical sensor. Radiation detector. 3. A radiation detector configured by arranging radiation detector channels two-dimensionally and converting incident radiation into an electric signal, wherein the radiation detector channel is provided on a radiation incident surface. And a mirror that reflects an optical signal from the scintillator in a substantially right-angle direction, and an optical sensor that is disposed substantially at a right angle to the incident surface of the scintillator and that converts an optical signal from the mirror into an electric signal. A radiation detector characterized in that a plurality of substrates parallel to the surface of the optical sensor are arranged, and a signal line for transmitting a detection signal is provided between the substrate and the optical sensor. 4. The radiation detector according to claim 1, further comprising a reflective material provided in a region between the scintillator and the optical sensor to prevent crosstalk between channels. 5. The radiation detector according to claim 1, wherein the optical sensor is a photodiode. 6. A CT apparatus, which captures a tomographic image of a subject using the radiation detector according to any one of claims 1 to 5.